1. Field of the Invention
The invention relates to a conveying apparatus used for a processing apparatus that executes predetermined processing on an article, to convey the article between a processing position for the processing apparatus and a wait position.
2. Description of the Related Art
A conveying apparatus disclosed in, for example, Japanese Patent Application Publication No. H07-148636 (JP H07-148636 A) has been available which loads and unloads an article such as a workpiece into and from a processing apparatus that processes the article, for example, a processing station for a machine tool. In JP H07-148636 A, a plurality of conveying apparatuses 100 is arranged between a plurality of processing stations arranged in alignment so as to consecutively execute processing. Each of the conveying apparatuses 100 includes a slide apparatus 1 on which a workpiece W is mounted in engagement with an engagement portion on an upper surface of the slide apparatus 1. The slide apparatus 1 loads and unloads the workpiece W into and from the processing station by sliding in a conveying (loading and unloading) direction of the workpiece W to enter the processing station.
At this time, the workpiece W is transferred between the slide apparatus 1 and the processing station using an elevating apparatus provided in the conveying apparatus 100. When the workpiece W is passed from the slide apparatus 1 to the processing station, first, the elevating apparatus is actuated to elevate the upper surface of the slide apparatus 1 (a mounting surface for the workpiece W) so as to align the upper surface with the height of the mounting surface for the workpiece W in the processing station, while bringing a protruding portion provided on the upper surface in engagement with a recessed portion formed in a lower surface of the workpiece W. The slide apparatus 1 is then slid toward the processing station along with the workpiece W to push the workpiece W into a mounting position (processing position) in the processing station. In this case, the mounting surface at the mounting position for the workpiece W in the processing station is shaped to receive only a part of an outer peripheral portion of the lower surface of the workpiece W. The slide apparatus 1, remaining engaged with the workpiece W, can advance to a delivery position (mounting position) for the workpiece W. Subsequently, the elevating apparatus is lowered to disengage the workpiece W from the slide apparatus 1 and to transfer the workpiece W to the mounting position in the processing station.
In contrast, when the workpiece W is moved from the processing station to the slide apparatus 1, the elevating apparatus is actuated to lower an upper surface of the conveying apparatus 100. The slide apparatus 1 is then slid toward the processing station, and the upper surface of the slide apparatus 1 is slid under the workpiece W located at the delivery position. Subsequently, the elevating apparatus is elevated to bring the lower surface of the workpiece W into engagement with the upper surface of the slide apparatus 1. The slide apparatus 1 is then slid away from the processing station. Thus, the workpiece W can be moved onto the upper surface of the slide apparatus 1.
Such conveying apparatuses 100 are each arranged between the processing stations arranged in alignment, so as to form a conveying path. Thus, the conveying apparatus 100 affects the line length of the processing stations, and the line length increases in proportion to the number of conveying apparatuses 100 arranged. In the technique in JP H07-148636 A, an expensive elevating apparatus is used to transfer the workpiece W between the conveying apparatus 100 and the processing station. Consequently, the conveying apparatus 100 involves a high cost.